• journal_title：Mineralogical Magazine
• Contributor：D. Atencio ; A. C. Roberts ; P. A. Matioli ; J. A. R. Stirling ; K. E. Venance ; W. Doherty ; C. J. Stanley ; R. Rowe ; G. J. C. Carpenter ; J. M. V. Coutinho
• Publisher：Mineralogical Society of Great Britain and Ireland
• Date：2008-
• Format：text/html
• Language：en
• Identifier：10.1180/minmag.2008.072.6.1201
• journal_abbrev：Mineralogical Magazine
• issn：0026-461X
• volume：72
• issue：6
• firstpage：1201
• section：Articles

d="p-1">Brumadoite, ideally Cu₃Te⁶⁺O₄(OH)₄·5H₂O, is a new mineral from Pedra Preta mine, Serra das Éguas, Brumado, Bahia, Brazil. It occurs as microcrystalline aggregates both on and, rarely, pseudomorphous after coarse-grained magnesite, associated with mottramite and quartz. Crystals are platy, subhedral, 1-2 μm in size. Brumadoite is blue (near RHS 114B), has a pale blue streak and a vitreous lustre. It is transparent to translucent and does not fluoresce. The empirical formula is d="inline-formula-1">d/tex-math-1.gif" />. Infrared spectra clearly show both (OH) and H₂O. Microchemical spot tests using a KI solution show that brumadoite has tellurium in the 6⁺ state. The mineral is monoclinic, P2₁/m or P2₁. Unit-cell parameters refined from X-ray powder data are a 8.629(2) Å, b 5.805(2) Å, c 7.654(2) Å, β 103.17(2)°, V 373.3(2) ų, Z = 2. The eight strongest X-ray powder-diffraction lines [d in Å,(I),(hkl)] are: 8.432,(100),(100); 3.162,(66),(d="inline-formula-2">d/tex-math-2.gif" />02); 2.385,(27),(220); 2.291,(12),(d="inline-formula-3">d/tex-math-3.gif" />22); 1.916,(11),(312); 1.666,(14),(d="inline-formula-4">d/tex-math-4.gif" />22,144); 1.452,(10),(323,040); 1.450,(10),(422,403). The name is for the type locality, Brumado, Bahia, Brazil. The new mineral species has been approved by the CNMNC (IMA 2008-028).